Glass used in automobiles, trucks, houses and commercial buildings have different requirements for visible transmissions. For example, the specification for visible transmission for cars is 70% in the United States, whereas the visible transmission for glass used in trucks and vans behind the driver (or B pillar) is typically 20-30%. The visible transmission for glass used in houses is about 75-80% and the visible transmission for glass used in buildings is generally from 20-40%.
It is often desirable to reduce the solar transmission for the glass used in each application. Glasses with reduced solar transmission used in autos and trucks may provide improved passenger comfort, reduced air conditioning loads and thus improved economy. This can also reduce sun damage to seating and interior components of the vehicles. Likewise, glasses with reduced solar transmission used in houses and buildings provide for reduced energy costs associated with air conditioning and reduced degradation of draperies and furniture.
Hence, for these applications, it may be desirable to reduce the solar transmission in glass.
Solar transmission can be adjusted by altering the chemistry of the glass. Alternately, the transmission characteristic of the glass can be altered by coating the glass with a material having specified pass characteristics. This latter technique can be done via chemical vapor deposition or physical vapor deposition coatings on the glass.
The prior art has found limited success with the first technique. For example, the best commercially available glass for autos has a solar transmission of about 40% and the best commercially available glass for trucks and vans (behind the B pillar) is about 23%.
Coatings, on the other hand, can often double or triple the cost of the glass product.
The present invention describes a new glass formulation and material which maximizes redox potential.